A water chair of the general type to which the present invention relates is disclosed in Australian Patent No. 527133 and corresponding U.S. Pat. No. 4,391,466. These patents relate to a water chair having back support cushions which are constituted by sling-supported water bags. The slings are attached in overlapping relationship to a hard, flat back of the chair and the water bags are located freely within the slings. A seat cushion for the chair is formed in a similar way, in the sense that it comprises a water bag which is located within a containing bag or cover, and the cushion is carried by a hard, flat support.
The water chair which is described and claimed in the referenced patents has received widespread approval, particularly when used by geriatrics who suffer pressure point discomfort when seated in conventionally upholstered chairs. However, it has been found that the water bags are subjected to considerable stress when water is displaced by concentrated forces and there is a risk that welded seams in the water bags might be subjected to such high stresses that they will burst. Also, it has been found that the water bags tend to fold or crease within the slings and that fatigue induced cracks can occur along the fold lines.